Arduino Due not recognized as new USB device

I've plugged my Due (via Programming Port) into my Win7 Professional system for the first time. It powers up and the yellow LED flashes, but the host system does not recognize it as a device -- it does not show the New Device balloons, nor display anything in the Device Manager. That sort of brings me to a full stop. Any suggestions on what I should do next? Thanks.

Cancel -- the USB cable I got from Radio Shack did not work, but the one from my Kindle did. Sorry about that.